周边气象条件对南京城区大气污染物浓度的影响

针对2014年8月南京国际青年奥林匹克运动会期间周边地区污染源的减排控制研究,本文将2010-2012年8月的NCEP/NCAR 的6 h再分析资料作为驱动场,利用WRF模式处理得到时空尺度更为精细的风场资料,结合南京奥体中心观测点的颗粒物及气体污染物浓度资料,通过相关分析以及合成分析,诊断得到了8月影响南京地区主要污染物的周边源区及其关键输送通道。结果表明：尽管8月青奥会时段南京地区主导风为海洋吹向大陆的东南风,但影响南京地区主要污染物（SO₂,NO₂,PM₁₀）浓度的外源及其主要输送路径各有不同。来自于南京西南部江西、湖南、湖北等地区的较远距离输送是对南京地区SO₂浓度影响的关键通道;来自于南京正南方向（安徽、浙江一带）的近距离输送是对南京地区NO₂浓度影响的关键通道;来自于南京西南部（湖北一带）的中远距离输送是对南京地区PM₁₀浓度影响的关键通道。     

Vibrating-Sliding Motion of Caisson Breakwaters Under Various Breaking Wave Impact Forces

Sliding is one of the principal failure types of caisson breakwaters and is an essential content of stability examination in caisson breakwater design. Herein, the mass-spring-dashpot model of caisson-base system is used to simulate the vi-brating-sliding motion of the caisson under various types of breaking wave impact forces, i.e., single peak impact force, double peak impact force, and shock-damping oscillation impact force. The effects of various breaking wave impacts and the sliding motion on the dynamic response behaviors of caisson breakwaters are investigated and the calculation of relevant system parameters is discussed. It is shown that the dynamic responses of the caisson are significantly different under different types of breaking wave impact forces even when the amplitudes of impact forces are equal. The amplitude of dynamic response of the caisson is lower under single peak impact excitation than that under double peak impact or shock-damping oscillation impact excitation. Though the disp